Revision of Canadian Eurytomidae (Hymenoptera, Chalcidoidea
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JHR 61: 1–29 (2017) Revision of Canadian Eurytomidae (Hymenoptera, Chalcidoidea)... 1 doi: 10.3897/jhr.61.13466 RESEARCH ARTICLE http://jhr.pensoft.net Revision of Canadian Eurytomidae (Hymenoptera, Chalcidoidea) associated with galls induced by cynipid wasps of the genus Diplolepis Geoffroy (Hymenoptera, Cynipidae) and description of a new species Y. Miles Zhang1,3, Michael W. Gates2, Joseph D. Shorthouse1 1 Department of Biology, Laurentian University, Sudbury, Ontario, P3E 2C6, Canada 2 Systematic Ento- mology Laboratory, National Museum of Natural History, Washington, DC, 20013, USA 3 Department of Biology, University of Central Florida, Orlando, Florida, 32816, USA Corresponding author: Y. Miles Zhang ([email protected]) Academic editor: Petr Jansta | Received 27 April 2017 | Accepted 13 November 2017 | Published 20 December 2017 http://zoobank.org/EC92424B-5657-41B6-958B-6DC26F827BE7 Citation: Zhang YM, Gates MW, Shorthouse JD (2017) Revision of Canadian Eurytomidae (Hymenoptera: Chalcidoidea) associated with galls induced by cynipid wasps of the genus Diplolepis Geoffroy (Hymenoptera, Cynipidae) and description of a new species. Journal of Hymenoptera Research 61: 1–29. https://doi.org/10.3897/jhr.61.13466 Abstract Eurytomids are small parasitic wasps associated with many communities of phytophagous insects. In most cases, the accurate identification of eurytomids is impeded by inadequate species descriptions that do not include figures of diagnostic features, and keys that are difficult to use. Here, diagnostic features and redescriptions are provided for both sexes of the eurytomids associated with galls induced by cynipid wasps of the genus Diplolepis Geoffroy found on shrub roses across Canada. Consequently, six species of Eurytoma Illiger, along with Tenuipetiolus ruber Bugbee, are dealt with. One new species, Eurytoma short- housei Zhang & Gates, sp. n., is described. Two species are synonymized, E. hebes Bugbee, 1973 and E. spina Bugbee, 1951 under E. longavena Bugbee, 1951, syn. n. Several new host and distribution records are reported. A dichotomous key is provided for both sexes of all seven species using photographs and scanning electron microscopy images. Keywords Eurytomidae, Diplolepis, Eurytoma, Tenuipetiolus, Canada Copyright Y. Miles Zhang et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. 2 Y. Miles Zhang et al. / Journal of Hymenoptera Research 61: 1–29 (2017) Introduction The interaction between insect herbivores and their associated natural enemies is one of the key factors in understanding the origin and evolution of multi-trophic systems. One particularly species-rich, ecologically-closed model system for studies of host-parasitoid relationships is the community of gall wasps (Hymenoptera: Cyn- ipidae) and their associated inquilines (e.g. Periclistus spp., Cynipidae: Diastrophini) and parasitoids (primarily Hymenoptera: Ichneumonoidea, Chalcidoidea) on oaks and roses (Csóka et al. 2005, Nicholls et al. 2010, Ronquist et al. 2015). Inquilines have lost their ability to induce galls, but still retain the ability to modify gall tis- sue (Brooks and Shorthouse 1997, Ronquist et al. 2015, Pujade-Villar et al. 2016). While entirely phytophagous, inquilines usually result in the death of inducers either through adult oviposition, or through competition for the same resources in the gall (Shorthouse 1973, 2010, Pujade-Villar et al. 2016). Parasitoids associated with cynipid galls feed either internally or externally as the host continues to develop (koinobionts), or when development of the host has been arrested by stinging prior to oviposition as for idiobionts (Csóka et al. 2005). Approximately 200 species of hymenopteran parasitoids are known from cynipid galls in Europe and North Amer- ica, most of which are gall-specific (Csóka et al. 2005). For instance, parasitoids associated with galls induced by Diplolepis Geoffroy, in particular the European spe- cies D. rosae L. (Stille 1984, Lázsló and Tóthmérész 2006, 2011, Lotfalizadeh et al. 2007c), the North American species D. polita (Ashmead), D. nodulosa (Beuttenmül- ler) (Brooks and Shorthouse 1997, Shorthouse 1973, 2010), and Diplolepis fructuum (Rübsaamen) in Iran (Lotfalizadeh et al. 2012) have been well studied. However, the taxonomy and ecology of many of these inquilines and parasitoids associated with Diplolepis are poorly known due to their small size and morphological conservatism (Shorthouse 2010). Members of the family Eurytomidae (Hymenoptera: Chalcidoidea) are one of the most common parasitoids associated with cynipid galls on roses in Canada, often com- prising up to 40% of the component community (Shorthouse 2010). Bugbee (1951a, b) reported 12 species of Eurytoma Illiger and one species of Tenuipetiolus Bugbee known from galls of Diplolepis, and suggested that most species are monophagous. Little is known about the host specificity of eurytomids in galls of the 14 species of Diplolepis found in Canada, but all species of Diplolepis are host to at least one species of Eurytoma (Shorthouse 2010, Zhang et al. 2014). Recent phylogenetic analyses redefined Eurytomidae as a monophyletic group (Lotfalizadeh et al. 2007b, Heraty et al. 2013). A gradual and mosaic evolution with large levels of homoplasy was observed within Eurytominae based on the study by Lotfalizadeh et al. (2007b). The genusTenuipetiolus Bugbee was grouped with Prode- catoma Ashmead based on the following derived states: 1) Adscrobal area with a dorsal depression or areola; 2) Epicnemium with a large and circular median areola dorsally; 3) Precoxal carinae close to anterior margin of metapleuron; 4) Submedian carinae close to each other. However, no formal synonymization has been proposed and all Revision of Canadian Eurytomidae (Hymenoptera, Chalcidoidea)... 3 four species of Tenuipetiolus are found restricted within Nearctic, associated with galls of cynipids and cecidomyiids (Bugbee 1951a). All species with a carinate gena and showing no other outstanding characters were redefined as Eurytoma sensu stricto (s.s.) with the following derived states: 1) Postgenal lamina present and raised ventrally over the surface of the postgena; 2) Postgena with a ventral depression between the posterior margin of the gena and the hypostomal fossa, with the depression delimited dorsally by a ridge or a step; 3) Gena with posterior margin slightly angulate above oral fossa (Lotfalizadeh et al. 2007b). Eurytoma s.s. is divided into 11 species groups including 700 nominal species worldwide, with ~100 Nearctic species north of Mexico (Lotfalizadeh et al. 2007b). Eurytoma associated with cynipid gall inducers have been placed under the rosae group, characterized by the presence of a precoxal tooth formed by the adscrobal carina (Lotfalizadeh et al. 2007b, see arrow in Fig. 11). Members of the rosae group often include cryptic species, which were morphologically indistinct or similar but with genetic and biological differences (Claridge and Askew 1960, Ács et al. 2002, Lotfalizadeh et al. 2007a, Gómez et al. 2011). The most recent published key to Nearctic Tenuipetiolus (Bugbee 1951a) and Eurytoma (Bugbee 1951b, 1967) is difficult to use due to the overlapping character states and the lack of illustrations. Additionally, current identification keys are limited to females, and thus the males are unidentifiable to species level. Biology of eurytomids associated with galls induced by Diplolepis Most eurytomids associated with galls induced by Diplolepis are univoltine. They feed throughout the summer on larvae of the gall inducer, inquilines, or on other parasitoids, overwinter as larvae within gall chambers, pupate in the spring and turn into adults (Shorthouse 1973). The emergence period of adults is synchronized with that of their host, which occurs soon after the immature galls appear such that the ovipositing females (Fig. 1) can reach the chambers of developing galls in this nar- row window of opportunity (Shorthouse 2010). Eurytomid eggs are brown to black, and with an elongated egg body, and a curved peduncle which may be used to attach the egg to the inside surface of the developing gall chambers or the body of its host (Fig. 2) (Vårdal et al. 2016). Eurytomid larvae in gall chambers with immature Diplolepis feed as koinobionts, keeping the inducer alive until the larva is fully grown and then consume it. This is necessary since the eurytomid larva grows to the same size as its single host. Euryto- mids commonly feed on gall tissues along the inside surface of galls after the inducer is consumed (Fig. 3), and as a result, maturing galls become lined with frass (Fig. 4), a characteristic sign of this parasitoid (Shorthouse 1973). Eurytomid larvae having emerged from eggs deposited in galls with immature Periclistus larvae feed as predators consuming many inquilines before the inquiline form chambers (Shorthouse 1973, Brooks and Shorthouse 1997). Eurytomids in Periclistus-modified galls then chew into the Periclistus chambers to consume larvae. 4 Y. Miles Zhang et al. / Journal of Hymenoptera Research 61: 1–29 (2017) Figures 1–5. Eurtyoma longavena 1 Female ovipositing into immature gall 2 Egg deposited on the inside surface of gall chamber 3 Mature larva inside a gall showing frass as a result of feeding on gall tissue 4 Pupa overwintering inside the gall before exiting the